Field of the Invention
The present invention relates to a vibrating body, a method of manufacturing the same and a vibration type drive device. More particularly, the present invention relates to a vibrating body including a piezoelectric element rigidly secured onto a substrate, a method of manufacturing the same and a vibration type drive device formed by using such a vibrating body.
Description of the Related Art
Piezoelectric elements have been popularly employed as vibration sources of vibrating bodies (to be also referred to as vibrators) in vibration type drive devices (vibration type actuators).
Piezoelectric elements include single plate piezoelectric elements and multilayered piezoelectric elements formed by laying a large number of piezoelectric layers recently (see Japanese Patent Application Laid-Open No. 2004-304887).
FIG. 8 is a schematic perspective view of a known linear type vibration wave (ultrasonic wave) drive unit 20 disclosed in the above cited Japanese Patent Application Laid-Open No. 2004-304887, representing an external appearance thereof. The illustrated linear vibration type drive device 20 includes a vibrating body 21 and a linear slider 26, which is brought into contact with the vibrating body 21 as pressure is applied to it and is a driven body.
The vibrating body 21 includes a multilayered piezoelectric element 23 and a vibrating plate 22. The multilayered piezoelectric element 23 is formed by alternately laying a plurality of piezoelectric layers and a plurality of electrode layers, while the vibrating plate 22 is made of metal and bonded to the multilayered piezoelectric element 23 by means of an adhesive agent that is made of resin.
The vibrating plate 22 that is made of metal includes a plate section formed to represent a rectangular contour and a pair of projecting sections 24 are formed so as to project from the top surface of the plate section. Contact sections 25 are formed respectively on the front end surfaces of the projecting sections 24. The contact (friction) sections 25 are made to have an abrasion-resistant property because they are members that are brought into direct contact with the linear slider 26 that is a driven body.
The vibrating body 21 of the linear vibration type drive device 20 is made to have a shape with which the resonance frequencies in two flexural vibration modes including the resonance frequency of the second order flexural vibration mode in the long axis direction and the resonance frequency of the first order flexural vibration mode in the short axis direction substantially agree with each other. Then, as two desired high-frequency voltages with phases different by about π/2 from each other are input, the vibrating body 21 is energized to cause the projecting sections 24 to make a circular motion or an elliptic motion.
The circular or elliptic motion by turn causes the linear slider 26 that is held in contact with the vibrating body 21 under pressure to produce a relative moving force due to the frictional force between the linear slider 26 and the vibrating body 21. Then, the linear slider 26 can linearly reciprocate as indicated by the arrows illustrated in FIG. 8 due to the relative moving force.
Such a multilayered piezoelectric element 23 is manufactured by firstly preparing a predetermined number of green sheets that operate as piezoelectric layers, using powder of a piezoelectric material and an organic binder by the doctor blade method and any others, and forming an electrode layer at a predetermined location on each of the green sheets by putting paste of an electrode material there by printing.
Then, the predetermined number of green sheets are laid flat one on the other and a multilayer structure is formed by applying pressure onto them. Thereafter, the piezoelectric layers and the electrode layers are integrated by means of simultaneous baking. Subsequently, a polarization process is executed and ultimately a finished multilayered piezoelectric element 23 is produced with predetermined dimensions by machining.
Meanwhile, Japanese Patent No. 2,842,448 proposes a piezoelectric/electrostrictive film type actuator having an integrated multilayered structure formed by sequentially laying an electrode material and a piezoelectric material on at least one surface of a substrate so as to form a multilayer structure and heat treating the multilayer structure.
Furthermore, Japanese Patent Application Laid-Open No. 2011-45869 proposes a vibrating body including a vibrating plate and a piezoelectric element having a piezoelectric layer and electrode layers, which is rigidly secured for the purpose of simultaneous baking and integration by interposing a ceramic layer that contains molten glass powder as glass ingredient between the vibrating plate and the piezoelectric element.